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Humanity has come a long way grasping the message since three scientists wrote the controversial book "Limits to Growth" in 1972, alerting us that resources of the earth are not infinite. Its 30-year update had a stronger warning that many resource and pollution levels had "overshot" beyond their "sustainable" limits; it foresaw disruption of economic systems if growth rates did not slow down. Today, as more nations seek consumption-based development, we continue to gobble up resources and pollute at ever increasing rates. And nature's distress signals get louder. But, rather than accepting them as omens of doom, we must take the opportunity to build sustainable economies. When the first sign of a global "overshoot" came in late 70's unexpectedly from the stratosphere, the world organized quickly. Montreal Protocol progressively banned ozone-depleting substances and the ozone hole over the Antarctic is now expected to heal by 2050. Meanwhile, nearby Australia is the world's skin-cancer capital. Global warming is another, grimmer, sign of an "overshoot." Greenhouse gas (GHG) emissions, from our stacks to exhaust pipes, far exceed the earth's capacity to absorb and they are changing the climate. Likely shifts in precipitation patterns and hence crop yields, disappearing snowcaps, rising sea levels… make regional catastrophes seem inevitable. We are urged to reduce emissions sharply and quickly. This is not an easy task but the Kyoto Protocol already took a first step forward. Climate predictions are based on modeling studies and, surely, modeling the climate is complicated. It has "chaotic" features (inherently unpredictable); most of its components have "non-linear" relationships (not proportional); has mechanisms that work with "delays" (if carbon dioxide emissions stop, atmospheric concentration will continue to rise for a while), or positive "feedbacks" (warming tundra releases GHG, causing more warming, in turn causing further release); and its suspected "thresholds" of "abrupt change" scare scientists (local sea warming beyond a point may stop the ocean current). Moreover, our time scale is minuscule compared to geological time. The earth had been in and out of ice ages over millions of years; we are interested in decades or centuries. There are other forces affecting the earth's climate such as variations in the earth's axis, or in sun's magnetic activity, tectonic movements, volcanism... Since the industrial revolution, GHG's appear to have outweighed them all. Their unprecedented levels for the last 800 thousand years indicate that we may be upsetting some balances; temperature hike within the last decades is alarming. However, we don't exactly know how much of these gases will continue to be absorbed, how much warming the excess will cause, or the responses of other mechanisms. To incorporate unknowns into models, we make assumptions, and run them on super-computers to make projections in time and space. These models are far from being flawless and even their basic assumptions are challenged. Yet, they reflect the level of scientific knowledge today, and they succeed in reproducing the present conditions from past data. It would be too risky to wait beyond possible "thresholds" of no return. On the other hand, going so far as to predict an apocalypse would neither be scientific, nor productive. Rather than predicting future events at "points" in time, long-term models project "behavior" of systems and help policy decisions by allowing comparison of alternative scenarios. "Short-term models" can make "point" predictions a few periods ahead. However, climate forecasts even for the near future are problematic. Let's remember the term "butterfly effect," used for fragility of chaotic systems, comes from meteorological models. (Can the flap of a butterfly in Brazil start/stop a tornado in Texas?) Climate of the earth will continue to change. We can control the human impact. From scientists to musicians, industrialists to mothers… we must work with confidence to revamp our economies. This suggests changes in life-styles but successful local examples exist from Denmark to China. All we need is political will. The monetary cost of transformation will not be nominal. But, for global warming, the recent Stern Review, prepared for the British Treasury, estimates that benefits of acting early far outweigh its cost on economies. And, as Lester Brown points out, by diverting only a portion of the billions dollars spent annually to promote GHG emitting activities (such as gasoline subsidies) we could be on course. With worldwide cooperation and use of renewable technologies, our civilization can certainly overcome this and the yet-unforeseen challenges, while still managing to improve the quality of our lives. And us individuals shall continue to "flap our wings" to help avert the tempest.
Article Source: http://www.solarpanelarticles.com
nukhet barlas senior environmental consultant, industrial engineer www.earthtale.com
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